Addition agent and two-cycle engine oil



United StatesPatent O 3,230,057 ADDITION AGENT AND TWO-CYCLE ENGINE DEL William L. Sielrer, Crown Point, Ind, assignor to Standard Oil Company, Chicago, Ill., a corporation of Indiana No Drawing. Filed July 31, 1961, Ser. No. 127,897 1 Claim. (Cl. 44-58) This invention relates to an addition agent combination capable of promoting cleanliness in an air cooled twocycle engine and further relates to a two-cycle engine oil containing the same.

The annual demand for oils used in spark-ignition twocycle engines is now about the annual volume of oils used by all diesel locomotives in the United States. More than 28 million gallons of motor oil were consumed in two-cycle engines in 1960, 22 million in outboard engines. More than 550 million gallons of gasoline were consumed with the oil.

The number of two-cycle engines has more than trebled since the end of World War II. Water-cooled outboard engines represent about half of the two-cycle engines in this country. The other half are air-cooled engines designed to power lawnmowers, chain saws, generators, pumps, go-karts, and other small equipment.

In spark-ignition two-cycle engines, the oil is mixed with the fuel in the fuel tank. The ratio of gasoline to oil consumption is normally about 20 to 1, compared with more than 100 to 1 for four-cycle engines used in passenger cars. A 75-H.P. two-cycle engine operating at wide-open throttle consumes about 40 gallons of oil in 100 hours, whereas a four-cycle engine of the same size may never use 40 gallons of oil in its lifetime. The large amount of oil burned in the combustion chambers of twocycle engines causes them to be more sensitive than fourcycle engines to motor-oil quality.

These engines offer simplicity of design and lightness in weight, and are economical to manufacture and maintain. Small size, high power output per pound, and the absence of an oil sump give the two-cycle engine versatility of operation. A good example is the chain saw, which must operate in any position.

Builders of two-cycle engines are actively engaged in a horsepower race reminiscent of that by automobile-engine builders several years ago. Outboard engines in particular have increased in horsepower to meet the boating and water-skiing enthusiasts desire for greater speed. Average outboard-engine horsepower reached 27.4 in 1960, and several companies now market 75- and 80-H.P. models.

The increase in horsepower of two-cycle engines has resulted in a demand for new and improved motor oils to meet severer lubrication requirements. The situation is similar to the need that developed during the 1950's for improved motor oils for high-horsepower passengercar engines. The petroleum industry, engine builders, and spark-plug manufacturers are devoting research effort to develop respectively better products.

Years ago, the low-power two-cycle engines were adequately lubricated with straight mineral oils developed for passenger cars. When motor oils were first compounded with detergent additives, the use of these products was extended to two-cycle engines. Almost immediately, users complained of spark-plug fouling and exhaust port plugging. As a result, the engine manufacturers recommended a return to straight mineral oils. During the past few years the rising horsepower of two-cycle engines has revealed deficiencies in straight mineral oils. Cooperative work between engine builders and 011 companies has led to apparent agreement that three common difficulties are: spark-plug fouling, piston varnish, and exhaust-port plugging.

3,230,057 Patented .llan. 18, 1966 T wo-cycle engines-particularly the large outboards are more susceptible to these problems than four-cycle engines. Horsepower per cubic inch of displacement is much higher and leads to higher operating temperatures. Spark-plug thermocouples in four-cycle passenger-car engines indicate 1000 to 12000 F, whereas temperatures in a -l-LP. outboard engine reach 1800" F. Such higher combustion-chamber temperatures increase the tendency for preignition, which further raises the temperature to about 2600 F. and leads to piston varnish, spark-plug fouling, and port plugging.

It has been known that straight mineral oils generally give inadequate performance in large outboard engines. in the formulation of two-cycle engine oils, it must be considered that such engine oils should provide good performance in both small, air-cooled engines and large, water-cooled outboard engines. I have now provided a combination of calcium sulfonate and lecithin as an addition agent for two-cycle engine oils. The combination can include the calcium sulfonate and lecithin in any ratio desired but preferably includes the two ingredients in a volume ratio in the range of about 1:1 to about 1:20, lecithinzactive calcium sulfonate. Higher or lower ratios, e.g. up to :1 of either ingredient based on the other may be used; excesses of either ingredient in the combination should not produce harmful effects.

The combination addition agent may be included in small amounts in a mineral lubricating oil, advantageously in amounts of from 0.1 to 10 volume percent and preferably from about 0.5 to 5 volume percent. The combination in lubricating oil can be added in the usual small amounts, e.g. in 1 to 15 volume percent, and more usually in amounts of 2 to 8 volume percent, in motor fuel to formulate a two-cycle engine fuel.

In order to demonstrate the compositions of this invention, the following were formulated:

Formulation A.-A combination addition agent consisting of 10 parts by volume synthetic calcium sulfonate (45% active sulfonate) obtained from Bryton Chemical Company and 1 part by volume lecithin.

Formulation B.A two-cycle engine lubricating oil consisting of SAE 30 grade mid continent solvent refined neutral mineral oil containing 2 volume percent of the 45% active synthetic calcium sulfonate and 0.2 volume percent of lecithin.

Formulation C.-A two-cycle engine fuel consisting of 16 parts by volume of a leaded premium grade gasoline (containing 3 cc.s tetraethyl lead per gallon) and 1 part by volume of Formulation B.

Additional formulations were prepared as follows for purposes of comparison with compositions of this invention:

Formulation D.The gasoline used in Formulation C plus the mineral oil defined in Formulation B in a volume ratio of 16: 1, gasolinermineral oil.

Formulation E.The composition of Formulation D except that the mineral oil contains 0.2% (voL) lecithin.

Formulation F.-The composition of Formulation D except that the mineral oil contains 2% (vol.) of the 45% active synthetic calcium sulfonate.

Formulations C, D, E, and F were subjected to the 96 hour Homelite Test, a test established by the Atlantic Refining Company for two-cycle engine oil additives. The test procedure and conditions are as follows:

Engine-Model 8A air-cooled Homelite, 7 HP. No. of cylinders l.

Q Q Test parts inspected-spark plugs, piston, cylinder liner.

Operating conditions:

Test duration 96 hours.

Speed Governed at 3600 rpm.

Load Applied by coupled electric generator.

Cycle 4 hours full load, 3 hours /2 load,

/2 hour no load, /2 hour engine stopped.

The results are reported in the table below as piston varnish rating, port plugging, closure and sparkplug failure, number failed. The piston varnish ratings are based on conventional coordinating Research Council (CRC) rating technique with the perfect rating being 10.0. Exhaust port plugging was rated as to the percent plugging of the original clean exhaust port. Spark-plug fouling is reported in terms of the number of occurrences during the test, as detected by a drop in engine load; if load could be restored by installing a new plug, sparkplug fouling was confirmed. In most cases the appearance of the plug left no doubt as to the fouled condition.

As a standard for rating the addition agents of this invention as completely acceptable for their intended purposes, the following are recent requirements of the Outboard Boating Club (OBC) as to sparkplug failure, port plugging and piston varnish:

Sparkplug failure No more than two spark-plug failures in any one cylinder in 100 hours.

Port plugging No more than in Watercooled engines and 25% in air-cooled engines.

Piston varnish CRC rating of 7.0 or better.

In the above tests, only the combination of this invention met and exceeded all requirements,

Although specific formulations set out above contained specific ingredients, it is to be understood that the invention is not limited thereto and that equivalents of such ingredients as fall within the scope of my contribution are fully intended.

The calcium sulfonate may be the calcium salt or soap of any sulfonic acid although some particular sulfonates may be more effective than others. Calcium sulfonate is prepared by neutralization of sulfonic acid with a basic calcium compound such as calcium oxide or calcium hydroxide. An example of useable calcium sulfonate is the calcium sulfonate prepared from the oil soluble petroleum sulfonic acids.

The petroleum sulfonic acids include the mahogany sulfonic acids, unsaturated paraifin wax sulfonic acids, petrolatum sulfonic acids, monoparaffin wax-substituted naphthalene sulfonic acids, diparafiin Wax substituted phenol sulfonic acids, wax sulfonic acids, petroleum naphthalene sulfonic acids, fuel oil substituted benzene sulfonic acids (synthetic alkyl aryl sulfonic acids), etc. The sulfonic acids also include diphenyl ether sulfonic acids, diphenyl ether disulfonic acids, naphthalene disul fide sulfonic acids, naphthalene disulfide disulfonic acids, diphenyl amine disulfonic acids, diphenyl amine sulfonic acids, thiophene sulfonic acids, alpha-chloronaphthalene sulfonic acids, cetyl chlorobenzene sulfonic acids, cetylsulfonic acids, cetyl-phenol disulfide sulfonic acids, cetylphenol mono-sulfide sulfonic acids, cetoxy capryl-benzene sulfonic acids, di-cetyl thianthrene sulfonic acids, di-lauryl beta-naphthol sulfonic acids, di-capryl nitronaphthalene sulfonic acids; hydroxy substituted paraffin wax sulfonic acids, tetra-isobutylene sulfonic acids, tetraamylene sulfonic acids, chloro-substituted paraffin wax sulfonic acids, nitroso parafiin wax sulfonic acids, cetylcyclopentyl sulfonic acids, lauryl-cyclo-hexyl sulfonic acids, monoand poly-wax subtituted cyclohexyl sulfonic acids, etc. Other useable oil-soluble sulfonic acids are well described in the art, for example, see US. 2,616,904; U.S. 2,626,207, and U.S. 2,767,209.

The sulfonic acids may be derived from various petroleum fractions such as gas oil, kerosene, light oil, turbine oil, mineral lubricating oil, heavy oil petroleum waxes (e.g. petrolatum paraffin wax and mixtures of various hydrocarbon Wax fractions,) etc.

For example, useable sulfonic acids may be produced in the acid treatment of petroleum mineral oil fractions such as mineral lubricating oil fractions with such agents as sulfuric acids or chloro-sulfuric acids. The petroleum sulfonic acids are well known to the art. Such petroleum sulfonic acids normally contain sulfonated aromatic constituents. They can be obtained, for example, by treating any normally liquid aromatic hydrocarbon-containing petroleum fraction with concentrated sulfuric acid or sulfur trioxide. A more particular petroleum sulfonic acid which is useable in this invention is the petroleum sulfonic acid obtained by sulfonating an aromatics-containing solvent extract from a 40-weight lubricating oil. Such sulfona-tion can be effected by treating the extract with sulfur trioxide or concentrated sulfuric acid. Petroleum sulfonic acids derived from lubricating oil stocks generally have a molecular weight within the range of from about 400 to about 700. Such sulfonic acids are oil-soluble and are commonly called mahogany acids as distinguished from the water soluble green acids. Although it is not known that the green acids would be useable because of inherent solubility problems, they may be effective in admixture with the mahogany acids or may even be useable in conjunction with a suitable solubilizer. Sulfonation of an aromatics-containing fraction produces a sulfonic acid-containing composition known in the art as sour oil. Although the sulfonic acids are normally extracted from sour oil before neutralization with calcium, the calcium sour oil sulfonates may be prepared directly without extraction and used herein.

Still other sulfonates are the calcium alkyl benzene sul'fonates including calcium-neutralized sulfonated mono-, diand polyalkyl benzenes obtained by sulfonation of aromatic hydrocarbons containing alkyl benzenes; the sulfonic acids from which these sulfonates are prepared by neutralization with calcium: generally have molecular weights in the range of from about 100 to about 200.

The additive combinations of this invention are useful in many lubricating oil bases for the purpose of imparting improved properties thereto, and to motor fuel compositions to which the lubricating oils are added. Although the utility of the addition agents has been demon strated hereinabove with reference to mineral lubricating oils, e.g. SAE 5 grade through SAE grade, the invention is not restricted thereto. Other lubricating oil bases can be used such as hydrocarbon oils both natural and synthetic, for example, those obtained by the polymerization of olefins as well as synthetic lubricating oils of alkene-oxide type and the polycarboxylic acid ester type such as the esters of adipic acid, sebacic acid, azaleic acid, and the like. It is also contemplated that other Well-known additives such as anti-oxidants, anti-foaming agents, extreme pressure agents, etc., may be incorporated in lubricating oils or motor fuels containing the additives of my invention if desired.

The motor fuels will preferably be gasoline but may be any other combustible liquid of suitable volatility employed as fuel for internal combustion-spark ignition engines, including paraflinic, naphthenic and aromatic hydrocarbons, isooctane and mixtures of isooctane with other suitable liquid hydrocarbons. The boiling point of such fuels should be in the range of from about 100 F. to about 500 F. and preferably in the range of from about 150 F. to about 400 F. Such motor fuels may also contain anti-oxidants, stabilizers, dyes, anti icing agents, lead scavenging agents and/or other compounds which are commonly employed in leaded motor fuels.

The combustion mixture can contain tetraethyllead equivalent to a concentration of from about 0.5 ml. to about 5 ml. or more per gallon of the hydrocarbon motor fuel employed. The concentration of tetraethyllead may be varied as is usual with the engine and its use. Unleaded fuels will be preferred from the standpoint of performance in the majority of two-cycle engines but, because of their greater availability, leaded fuels will more generally be used.

All percentages herein and in the appended claims are percents by volume unless otherwise indicated.

Reports from two-cycle engine manufacturers indicate that an improvement is needed in two-cycle engine oils before outputs of these engines can be increased any further. The combination of calcium sulfonate and lecithin provides a way of minimizing harmful deposits and allow increased specific output in two-cycle engines.

I claim:

A two-cycle engine fuel consisting essentially of leaded gasoline containing about 6 volume percent total of SAE 30 grade mineral lubricating oil, lecithin and an oil soluble calcium petroleum sulfonate, said lecithin being present in an amount of about 0.2 volume percent based on lubricating oil and said calcium. sulfonate being present in an amount of 0.9 volume percent active calcium sulfonate based on lubricating oil.

References Cited by the Examiner UNITED STATES PATENTS 2,322,007 6/1943 Fischer 44-58 2,366,817 1/1945 Towne 252-334 2,370,080 2/1945 Schreiber 252-325 X 2,991,163 7/1961 Sipos et a1. 44-66 3,015,320 1/1962 Brennan et al, 44-58 X 3,020,134 2/1962 Keller et al. 44-58 3,034,875; 5/1962 Buckzmann 44-58 3,083,162 3/1963 Lawrence 44-58 3,085,978 4/1963 Metacek et a1. 252-33.4

FOREIGN PATENTS 503,599 6/1954 Canada. 1,024,749 2/ 8 Germany.

795,390 5/ 1958 Great Britain.

795,658 5/1958 Great Britain.

OTHER REFERENCES Lubrication Problems in Two-Stroke Petrol Engines in Scientific Lubrication, March 1959, pp. 12-20 relied on.

DANIEL E. WYMAN, Primary Examiner.

JULIUS GREENWALD, Examiner. 

